The EU referendum campaign is looking more each day like a "blue-on-blue" political knife fight; no longer a question of which side has the best ideas for Britain's future.

Instead, the prime minister and his senior ministerial colleagues on either side of the European divide are competing to convince the country their rivals are the worst liars.

David Cameron declined to use the "l" word today, but he didn't need to.

This will hurt the Conservative Party. It will damage the credibility of senior ministers. It will erode trust in government departments like the Treasury, where some degree of trust is essential.

It will eat away at whatever may be left of public faith in the political process. And it will make David Cameron's job reuniting his party - assuming he survives the vote - much harder.

Far more worrying for the Remain side - and encouraging for the Leavers - is that, just now, the grotesque self-harm the Conservative Party is inflicting upon itself is beside the point.

'Playing catch up'

Comparatively unnoticed, cast into shadow by the pyrotechnic light-show in the Tory party, the Labour Party has come to realise it is losing the argument, and may be in real danger of losing the referendum for the Remain campaign.

This morning, Labour's shadow cabinet agreed the party needed to "up its game" and to do so urgently. Alarmed backbench MPs have been excusing themselves from parliamentary duties to kick-start what they describe as the near-torpid campaigning in their constituencies.

MP after MP has returned to Westminster with depressing tales from their home turf; of door-knocking in staunchly Labour areas where apathy towards the EU question has given way to rank hostility. One former minister contacted dozens of local Labour councillors urging them to mobilise behind the Remain campaign. To the MP's fury, the appeal elicited one single reply.

Image copyrightReutersImage caption
Jeremy Corbyn (r) and Tom Watson launch a poster as part of Labour's In campaign

Among the most ardent pro-Europeans on the Labour side, there is private frustration that leader Jeremy Corbyn has not been more active in support of the cause. Yet at today's shadow cabinet, Mr Corbyn is said to have shared the general sense of alarm.

Often, according to another shadow minister, the antipathy to the EU has little or nothing to do with Europe. "People just want to kick the establishment," he said.

Another shadow cabinet member told me: "We have never really set out to make the case for Europe. The sceptics have been winning the argument by default. Now we're playing catch up."

So the word has been sent out to energise the support for British membership of the EU among Labour voters.

There is still just over a fortnight of campaigning to come. The outcome is not settled.

But among Labour MPs representing areas which will be crucial to the outcome of the referendum, the nagging fear is starting to take hold that it may already be too late.